Saw-blade.



UNITED STATES PATENT OFFICE.

IIIRAM II. BICKFORD, OF ELMIRA, NElV YORK.

SAW-BLADE.

SPECIFICATION forming part of Letters Patent No. 657,155, dated September 4, 1900. Application filed January 11, 1900. Serial No. 1,114. (No model.)

To (LY/Z whom it may concern.-

Be it known that I, HIRAM I-I. BIOKFORD, a citizen of the United States,residingat Elmira, in the county of Chemung and State of New York, have invented a new and useful Improvement in Saw-Blades for Stone-Cutting, of which the following is a specification.

My invention relates to improvements in the blades employed in saws for cutting stone; and the object of my improvements is to provide a saw-blade of this type which shall be more effective and efficient than those now in use.

I'Ieretofore it has been customaryin cutting large blocks of stone into slabs and the like to employ a horizontally-reciprocating gangsaw, the blades of which are composed of narrow homogeneous strips of steel. These blades are reciprocated across the stone under pressure, a mixture of sand or otherabrasive material and water being fed thereto to produce an abrading action of the steel upon the stone and the cutting away of the stone thereby. The blades being homogeneons wear away evenly along their cutting edge, and the sand and water reach the cutting edge only as they flow down the sides of the blades. I propose to so change the structure of these saw-blades as to provide pockets in which the sand and water may accumulate at a number of points along the cutting edge in order that the sand may be presented to the blade across its entire thickness. In order to accomplish this end properly, the blade must be so constructed that these pockets will be maintained as the blade is worn away. I accomplish my object by constructing these sawblades in the manner illustrated in the accompanying drawing, wherein I have represented a saw blade of the form now in general use, indicating thereon how I propose to to treat this blade to accomplish the end in view.

The blade A consists of a flat straight edged strip of iron or steel provided at the ends with holes or other means for attaching it to the saw-frame. Intermediate the ends I temper or otherwise harden a number of different sections at B B B B, the portions of the blade between these hardened sections being left in their original condition. The blade is thus made up of a series of alternate hardened and soft portions extending transversely across the width and thickness of the blade, the number and relative length of these sections being arranged to suit requirements asthey may develop.

In operation as soon as the blade is set in motion across the stone the softer portions will be cut away in advance of the harder portions, as indicated by the broken lines at a a a, thereby forming in front of and between the hardened portions pockets into which the sand and water will flow and cansing the sand to be presented to the hardened portions across their entire thickness, consequently adding to the effectiveness of the saw-blade and rendering the cutting action more rapid without an increase of speed in the saw. As the edge of the blade wears away the softer portions will continue to be cut away in advance of the harder portions, thereby assuring the formation of these pockets automatically throughout the entire life of the blade.

I am aware that saw-blades have heretofore been constructed of combined plates having different degrees of hardness and also that saw-blades have been made with the entire cutting edge tempered, the body of the blade being left soft.

WVhat I claim as my invention, therefore, and desire to secure by Letters Patent, is

1. A one-piece saw-blade, having alternate transverse sections thereof tempered or otherwise hardened, as and for the purpose set forth.

2. A saw-blade for stone-cutting compris ing a fiat straight edged strip of iron orsteel composed of alternate hard and soft sections running transversely across the blade.

In testimony whereof I have afflxed my sig-' nature in presence of two witnesses.

IIIRAM II. BIOKFORD.

Witnesses:

WALTER B. OLMSTED, WILLIAM C. J ORDAN. 

